Ukrainian troops engaged in a “counter-terror” operation in the Eastern city of Sloviansk on Thursday which sparked clashes around the unstable area of the country which borders Russia. A subsequent operation in the city of Mariupol is said to have resulted in the retaking of a local administrative building from separatists, according to Ukraine’s Interior Minister Arsen Avakov.

Reports indicate that five people were killed in the raids. “Ukraine’s acting President, Olexander Turchynov, called on Russia to pull back its troops from the border and end what he called its “blackmail”, adding that Kiev would not yield to “Russian-backed terrorists,” the BBC reports.

Watch professional footage of the raid below via RafaVideoart:

Watch an amateur video below via Kai Cain:

Moscow officials have condemned the attack on pro-Russian separatists in the East and warned of consequences for Kiev’s actions. Shortly after the raids, large amounts of Russian troops amassed along the border began making coordinated movements.